Photochromic Ion Channel Blocker, QAQ

A membrane-impermeant Na⁺, K⁺, and Ca²⁺ channel blocker that is structurally composed of two azo-linked QX-314 (Cat. No. 552233) type quaternary amines. Both QX-314 and QAQ are shown to selectively target excitability of nociceptor neurons via TRPV1-dependent cellular uptake upon TRPV1 activation by Capsaicin (Cat. No. 211275). Unlike QX-314, the channel blocking potency of QAQ can be quickly switched off by an optical trans to cis isomerization upon 320 nm illumination, which in turn can be reversed back to the active trans configuration via 500 nm illumination. Its in vivo efficacy as a pain-selective, photochromic anesthetic has been demonstrated in modulating rat cornea tolerance to mechanical pressure (200 nmol QAQ/100 pmol Capsaicin/10 µl/eye). QAQ cellular uptake can also be achieved by ATP-activated P2X₇ receptor, but not activated TRPA1 or TRPM8. In addition, QAQ is reported not to affect K_ir (inward-rectifier) or HCN (hyperpolarization-activated cyclic nucleotide-gated) channels.

Cell permeable: no

Primary Target
Ion Channels

Reversible: yes

Packaged under inert gas

Following reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 3 months at -20°C.

Mourot, A., et al. 2012. Nat Methods.9, 396.
Banghart, M., et al. 2009. Angew Chem Int Ed Engl.48, 9097.

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Toxicity: Standard Handling (A)